A hybrid vehicle incorporating an internal combustion engine and a motor as driving sources controls the driving and stopping of the engine and electric motor according to the running state, thereby driving the wheels by use of the torque of only the electric motor or driving the wheels by use of the torques of both the engine and electric motor.
For example, a hybrid driving device, described in Patent Document 1 specified below, has separately a first power transmission device for transmitting power from an engine to a counter shaft via a power distribution mechanism and a second power transmission device for transmitting power from a second motor generator to the counter shaft. This hybrid driving device appropriately sets a transmission gear ratio of each transmission device, thereby decreasing energy loss in high speed running, without degrading gradient performance.